System Development Life Cycle

Problem Solving Methodology

analyse, design, develop, [test, document,] implement, evaluate

In brief:

You need to go through certain boring and painful but vital steps (the System Development Life Cycle - SDLC - or Problem Solving Methodology - PSM) to reliably solve an information problem.

If the problem is big enough, you need to manage the problem-solving process by treating it as a project to make sure that tasks are on time and on budget. This is called the Project Life Cycle.

Note: The 5 steps of the SDLC are the same as those in the 'problem solving methodology' used by ITA and year 11. The only difference is that they add Testing and ITA also adds Documentation for one outcome. Details below.

If the problem is complex, it is worth solving it by treating it as a project to manage the process of solving it. A project, after all, is just two or more people using sensible steps to solve a problem with limited resources and time.

To solve an information problem, you need to go through the problem solving steps called the the System Development Life Cycle. Since the SDLC and the PSM are basically identical, consider them interchangeable here.

1. Analyse the problem - define necessary input, output, storage etc regardless of what solution is used. Define what the problem really is. State a goal to be achieved.

Also see What is an information problem?

2. Design the solution - seek alternative solutions, pick the best, describe how it works in detail.
3. Develop the solution - write code, build hardware, plug things in.
3a. Test the solution - make sure it works according to specifications (because it's not a separate step in the SDLC, this step is carried out during development)
3b. Document the solution - for all users (operators, technicians, customers, managers) (because it's not a separate step in the SDLC, this step is carried out during implementation)
4. Implement the solution - install it, train the users, .
5. Evaluate the solution - make sure the solution really has solved the original problem.

Note: there are different 'flavours' of the SDLC depending on where you go and who you read. The exam will adopt the 5-step SDLC model (analyse, design, develop, implement, evaluate), but the exam should list the steps it recognises.

Be aware that while there are different SDLC models, they all include basically the same concepts. It's just that some models might break one of the "5 steps" into separate steps (e.g. testing, documentation), or combine steps into one.

Whichever model you find, they should all be essentially similar.

SDLC Step 1: Problem Analysis

SDLC Step 2: Design the Solution

Design details are here

SDLC Step 3: Develop the Solution

Once the system has been designed in detail, it can be developed. this is the fun bit where a system is built or changed. The three main steps in developing a system are:

• Software acquistion (creating it or buying it)
• Hardware acquisition (creating it or buying it)
• Assembly of the system
• Informal testing

The designed actions are carried out. There should be no big surprises here if the design was thorough. System development often ends with acceptance testing, where the builders of the system prove it works.

PSM step 3a: Test the Solution

This step appears independently in the Problem Solving Methodology used by ITA and IT11.

Details on testing are here

PSM step 3b: Document the Solution

Document the solution

The best way to decide what documentation is required, cheerfully assume that every staff member using the solution will be tragically killed by meteors the day after the solution is brought online. After they hose down the office, could new workers be brought in and start working effectively and efficiently using the documentation you have provided?

In real life, people quit, retire, move to new departments or get killed by falling elephants. If Joan, the payroll lady, suddenly quit it is possible that she would be the only one who could do the payroll. Getting a new worker to understand and use the system could take quite a long time.

Good documentation of hardware, software and procedures is vital for new staff and also when trouble strikes - such as equipment breakdown. Documentation should be good (click here for discussion of that) and it must be kept up to date if it's going to be of any use.

Documentation needs to consider everyone who will come in contact with the system: operators, the public?, managers, technicians. They all have different needs and each one will need different types of documentation to let them learn the system or use it effectively and efficiently.

SDLC Step 4: Implement the Solution

Implementation details are here

SDLC Step 5: Evaluate the Solution

Evaluation details are here